Isobutyric acid (iHOBu) has a number of commercial uses and is an intermediate in the manufacture of a number of esters and other compounds that have a variety of uses. A widely used way of making iHOBu is through the catalyzed or uncatalyzed oxidation of isobutyraldehyde (iHBu). Such oxidation processes have the problem of the formation of undesired byproducts. One such product is isopropyl formate (IPF). Some other examples of byproducts include carbon dioxide, isopropanol, propane, propylene and acetone.
While not wanting to be bound by a particular theory, it has been theorized that IPF is produced by the Baeyer-Villiger oxidation of isobutyraldehyde. This theorized mechanism is depicted in FIG. 1. According to this theory, the oxidation of the aldehyde results in the formation, first of peroxyacid, followed by the generation of an intermediate that can lead to production of two moles of the desired acid (Pathway A) or one mole of the desired acid and one mole of the undesired byproduct IPF (Pathway B). Pathway B is believed to result in the loss of some of the iHBu feed to form of the undesired byproduct IPF.
Formation of these byproducts consumes valuable raw materials and lowers the production of the desired acid. There are other drawbacks. For example, IPF byproduct is very difficult to separate from unreacted starting materials. Separated IPF from the crude product composition often includes unreacted isobutyraldehyde (iHBu) due to the proximity of their boiling points. Accordingly, the formation of IPF by-product is a significant financial burden on commercial production of isobutyric acid. Formation of non-IPF byproducts consumes raw materials and occupies volume in process equipment. It would therefore be beneficial to reduce or to eliminate formation of IPF in such processes.